gcc: add zstd support
gcc: add zstd support

This enables the use of `zstd` instead of `zlib` for LTO data
compression. Compression with `zstd` is 4-8x faster than with `zlib`. [1]

This is, for practical purposes, part of the default GCC configuration,
since GCC's build system will enable `zstd` support when it discovers
that `zstd` is available in the build environment. We pass the
`--with-zstd` flag anyway to make sure it uses a brewed `zstd` for that.

Closes Homebrew/linuxbrew-core#22800.

[1] https://gcc.gnu.org/legacy-ml/gcc/2019-06/msg00185.html

Closes #77985.

Signed-off-by: Sean Molenaar <2b250e3fea88cfef248b497ad5fc17f7dc435154@users.noreply.github.com>
Signed-off-by: FX Coudert <c329953660db96eae534be5bbf1a735c2baf69b5@gmail.com>
Signed-off-by: BrewTestBot <8a898ee6867e4f2028e63d2a6319b2224641c06c@users.noreply.github.com>

stgraber/homebrew-core,mbcoguno/homebrew-core,zyedidia/homebrew-core,lemzwerg/homebrew-core,mfikes/homebrew-core,Moisan/homebrew-core,uyjulian/homebrew-core,Homebrew/homebrew-core,chrisfinazzo/homebrew-core,lemzwerg/homebrew-core,mbcoguno/homebrew-core,stgraber/homebrew-core,nbari/homebrew-core,uyjulian/homebrew-core,makigumo/homebrew-core,cblecker/homebrew-core,filcab/homebrew-core,sjackman/homebrew-core,nandub/homebrew-core,adam-moss/homebrew-core,makigumo/homebrew-core,JCount/homebrew-core,chrisfinazzo/homebrew-core,Moisan/homebrew-core,JCount/homebrew-core,Linuxbrew/homebrew-core,sjackman/homebrew-core,zyedidia/homebrew-core,filcab/homebrew-core,mfikes/homebrew-core,cblecker/homebrew-core,Linuxbrew/homebrew-core,adam-moss/homebrew-core,nandub/homebrew-core,Homebrew/homebrew-core,mbcoguno/homebrew-core,nbari/homebrew-core